A colorful ad appearing in several Oregon newspapers this month urges readers in Oregon to "Start a revolution with a tomato." An environmental group paid for the ad because it wants Americans to think about the tomatoes and other produce they buy, and who grew them.

For America's tomato lovers, this is a great time of year because they can get tasty, vine-ripened, homegrown tomatoes. A Portland-based group called Ecotrust says there's a reason tomatoes taste so good now, and so bland the rest of the year: when the crop isn't in season in North America, tomatoes are picked green and ripen on the way to grocery shelves.

"We're losing small family farms," she said. "The average age of a farmer is 54 in Oregon. Very few folks are going into farming. Our food travels an average of 1,500 miles from farm to plate. There's something wrong here."

Ms. Brady says Oregon raspberry farmers, for example, are forced to compete with Chilean raspberry producers, and she says the home team is losing. But she says consumers can change things by considering more than price in the grocery store and voting with their dollars.

"We have created a commodity agriculture system so that the main thing people are buying and growing, is based on price," continued Eileen Brady. "And the future of our food system really depends on turning that upside down: people choosing quality, producers producing quality products where the attribute is not only price. It's about who grew the food, about what the environmental standards are of the organizations that grew the food and produced the food and sold the food."

But the Ecotrust campaign goes beyond an effort to save local farmers. It's also political. A headline in the newspaper ad says "Buy local and Live Free," and goes on to ask whether Americans are really free if most of their food comes from some faraway mega-corporation.

Dave Zepponi, president of the Northwest Food Processors Association, supports the buy local message. But he says the political message makes him uncomfortable.

"I don't think it's appropriate to take it to the next level and make it political," he said. "This is something that I think should stay in the realm of the consumer."

Mr. Zepponi sees campaigns like this as part of an emerging buy local niche market, similar to the one created by organic food movement. But he doesn't think the concept will change the nation's food production industry.

"Generally speaking, most people want to have an inexpensive food supply," said Dave Zepponi. "They want to be able to go to the store and buy a food at a very inexpensive price. This [campaign] is going to drive the price higher."

Ecotrust's campaign is part of a larger effort that Karen Lewotsky says is happening all over the world. Her group, the Oregon Environmental Council, has launched a similar buy-local campaign, urging lawmakers to pass a bill requiring state agencies, such as the Department of Corrections, to buy local products.

"That hasn't gone anywhere," she said. "However, we've been working with the Department of Agriculture and many other folks who're involved in the conversation to try to promote that on a voluntary level so that state agencies, wherever possible, can implement that at their own discretion."

Ms. Lewotsky doesn't have any illusions that American consumers will switch, en masse, to buying local products. But she says that doesn't have to happen.

"Where we can, we buy stuff local," said Karen Lewotsky. "But there aren't any Oregon farmers growing bananas and there aren't ever going to be any Oregon farmers growing bananas. So if you want a banana, you're going to have to figure out where to buy it from."

Getting consumers to ask that question is the main goal of campaigns such as hers. She says, knowing where food comes from and thinking about who produces it may be enough to change future buying habits.